Melanotic Xp11 translocation renal cancer: report of a case with a unique intratumoral sarcoid-like reaction

Splenic sarcoid reaction mimicking metastases in patients after uterine cancer surgery: a report of two cases

BACKGROUND

Tumor-associated sarcoid reactions have been observed with various tumors; however, they have not been reported with uterine cancer. We present two cases of splenic sarcoid reactions that mimicked metastases a few years after uterine cancer surgery.

CASE PRESENTATION

Case 1 involved a 67-year-old female patient diagnosed with endometrial cancer (pT1aN0M0, pStage Ia, grade 1). The patient underwent open total abdominal hysterectomy and bilateral salpingo-oophorectomy with pelvic lymphadenectomy. Three years after the initial surgery, computed tomography (CT) and positron emission tomography CT showed multiple splenic masses with increasing numbers and sizes. Splenic metastases were diagnosed, and laparoscopic splenectomy was performed. The histopathological analysis revealed sarcoid reactions in the spleen. Case 2 involved a 47-year-old female patient diagnosed with endometrial cancer (pT1aN0M0, pStage Ia, grade 1). The patient underwent laparoscopic total abdominal hysterectomy and bilateral salpingo-oophorectomy with pelvic lymphadenectomy. Two years after the initial surgery, multiple splenic masses were observed. We performed laparoscopic splenectomy for the splenic metastases. Granuloma formations were identified in the splenic specimen and perisplenic lymph nodes that were removed simultaneously, resulting in a final diagnosis of sarcoid reaction. A review of the lymph nodes at the time of the previous uterine surgery revealed granuloma formation. Other than the presence of splenic masses, no findings suggestive of recurrence were observed in these cases. Uterine cancer and sarcoid reactions progressed without recurrence after splenectomy.

CONCLUSIONS

To the best of our knowledge, this is the first report of the late development of splenic sarcoid reactions after uterine cancer surgery. Sarcoid reactions and metastases are difficult to diagnose based on preoperative imaging results. However, reviewing the specimen at the time of the initial resection, the number of lesions, and the clinical findings (other than imaging findings) may aid in the determination of the correct diagnosis.

Angiomyolipoma of the kidney: from simple hamartoma to complex tumour

Angiomyolipoma is the most common mesenchymal tumour of the kidney, even if for a long time it has been viewed as a hamartoma rather than a neoplasm. It belongs to a family of neoplasms, named PEComa, characterised by the constant presence of perivascular epithelioid cells that co-express smooth muscle and melanogenesis markers. Angiomyolipoma can occur in patients with tuberous sclerosis, a hereditary syndrome due to the alteration of TSC1 or TSC2 genes, or sporadically. Angiomyolipoma and its variants are indolent tumours; however, some epithelioid angiomyolipomas/pure epithelioid PEComas are aggressive, and criteria for malignancy have been proposed to identify those cases. Although typical angiomyolipoma is a straightforward diagnosis, pathologists should be aware of the wide morphological spectrum of its variants which could be tricky in routine clinical practice and could require immunohistochemical analysis for resolution. The differential diagnosis may range from an inflammatory process (for instance xanthogranulomatous pyelonephritis) to the most common renal cancers and sarcomas. The immunoexpression of melanogenesis markers (HMB45 and Melan-A) and cathepsin K is extremely helpful in the majority of cases. Recently, a subset of epithelioid angiomyolipoma/pure epithelioid PEComa harbouring TFE3 gene fusions has been described, raising questions about its relationship with the family of perivascular epithelioid cell tumour. The activation of the mTOR pathway due to genetic alterations of tuberous sclerosis complex in TSC1 or TSC2 genes in angiomyolipoma has also been reported as well as the subsequent therapeutic implications.

Malignant melanotic Xp11 neoplasms exhibit a clinicopathologic spectrum and gene expression profiling akin to alveolar soft part sarcoma: a proposal for reclassification

The classification of the distinct group of mesenchymal neoplasms, first described as 'Xp11 translocation perivascular epithelioid cell tumor (PEComa)' and for which the term 'melanotic Xp11 neoplasm' or 'Xp11 neoplasm with melanocytic differentiation' has recently been proposed, remains challenging and controversial. We collected 27 melanotic Xp11 neoplasms, the largest series to date, for a comprehensive evaluation. Fourteen of the cases, together with eight alveolar soft part sarcomas (ASPS), nine conventional PEComas and a control group of seven normal tissues were submitted to RNA sequencing. Follow-up available in 22 patients showed 5-year overall survival and 5-year disease-free survival of 47.6 and 35.7%, respectively, which were similar to ASPS and significantly worse than conventional PEComa. Univariate analysis of location (occurring in the kidney versus not kidney), infiltrative growth pattern, nuclear pleomorphism, mitotic activity ≥2/50 high-power fields (HPF), necrosis and lymphovascular invasion were found to be associated with overall survival and/or disease-free survival. Multivariate analysis identified that location was the only factor found to independently correlate with disease-free survival. More importantly, RNA sequencing-based clustering analysis segregated melanotic Xp11 neoplasm and ASPS from other tumors, including conventional PEComa and Xp11 translocation renal cell carcinoma, and formed a compact cluster representative of the largely similar expression signature. Here we clearly define the true biologic nature of melanotic Xp11 neoplasms which are distinctive malignant mesenchymal tumors, rather than simply PEComa variants with occasionally unpredictable behavior. Meanwhile, melanotic Xp11 neoplasm and ASPS more likely represent phenotypic variants of the same entity, which is distinct from conventional PEComa and Xp11 translocation renal cell carcinoma. Based on these important findings, melanotic Xp11 neoplasm might be reclassified into a distinctive entity together with ASPS, independent from PEComa, in future revisions of the current WHO categories of tumors of soft tissue and bone for the improved reclassification. © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

RNA sequencing of Xp11 translocation-associated cancers reveals novel gene fusions and distinctive clinicopathologic correlations

Both Xp11 translocation renal cell carcinomas and the corresponding mesenchymal neoplasms are characterized by a variety of gene fusions involving TFE3. It has been known that tumors with different gene fusions may have different clinicopathologic features; however, further in-depth investigations of subtyping Xp11 translocation-associated cancers are needed in order to explore more meaningful clinicopathologic correlations. A total of 22 unusual cases of Xp11 translocation-associated cancers were selected for the current study; 20 cases were further analyzed by RNA sequencing to explore their TFE3 gene fusion partners. RNA sequencing identified 17 of 20 cases (85%) with TFE3-associated gene fusions, including 4 ASPSCR1/ASPL-TFE3, 3 PRCC-TFE3, 3 SFPQ/PSF-TFE3, 1 NONO-TFE3, 4 MED15-TFE3, 1 MATR3-TFE3, and 1 FUBP1-TFE3. The results have been verified by fusion fluorescence in situ hybridization (FISH) assays or reverse transcriptase polymerase chain reaction (RT-PCR). The remaining 2 cases with specific pathologic features highly suggestive of MED15-TFE3 renal cell carcinoma were identified by fusion FISH assay. We provide the detailed morphologic and immunophenotypic description of the MED15-TFE3 renal cell carcinomas, which frequently demonstrate extensively cystic architecture, similar to multilocular cystic renal neoplasm of low malignant potential, and expressed cathepsin K and melanotic biomarker Melan A. This is the first time to correlate the MED15-TFE3 renal cell carcinoma with specific clinicopathologic features. We also report the first case of the corresponding mesenchymal neoplasm with MED15-TFE3 gene fusion. Additional novel TFE3 gene fusion partners, MATR3 and FUBP1, were identified. Cases with ASPSCR1-TFE3, SFPQ-TFE3, PRCC-TFE3, and NONO-TFE3 gene fusion showed a wide variability in morphologic features, including invasive tubulopapillary pattern simulating collecting duct carcinoma, extensive calcification and ossification, and overlapping and high columnar cells with nuclear grooves mimicking tall cell variant of papillary thyroid carcinoma. Furthermore, we respectively evaluated the ability of TFE3 immunohistochemistry, TFE3 FISH, RT-PCR, and RNA sequencing to subclassify Xp11 translocation-associated cancers. In summary, our study expands the list of TFE3 gene fusion partners and the clinicopathologic features of Xp11 translocation-associated cancers, and highlights the importance of subtyping Xp11 translocation-associated cancers combining morphology, immunohistochemistry, and multiple molecular techniques.

Melanotic Xp11 translocation renal cancer: a report of a distinctive case and a review of the literature

BACKGROUND

Melanotic Xp11 translocation renal cancer (TRC) is a newly described exceedingly rare tumor, and its characterization remains controversial. This study aimed to describe a case of distinctive melanotic Xp11 TRC and to elucidate its clinicopathological and molecular genetic features.

CASE PRESENTATION

A 44-year-old Chinese female presented with a left renal mass. Abdominal ultrasonography and computed tomography (CT) scans revealed a 4.5 cm × 4.0 cm mass in the left kidney. Grossly, the well-demarcated mass was black with moderately firm consistency. Microscopic examination indicated that the tumor was characterized by the presence of nests and cords of polygonal cells with clear and granular eosinophilic cytoplasm, central round to oval nuclei and occasional nucleoli. Intracytoplasmic melanin was observed in approximately 45% of tumor cells. Uniquely, the tumor presented with intranuclear eosinophilic pseudoinclusions and thick-walled stromal blood vessels. IHC showed that tumor cells were diffusely positive for TFE3 and exhibited patchy and weak HMB45 staining. FISH confirmed the presence of TFE3 rearrangement.

CONCLUSION

This case is the twentieth published case of melanotic Xp11 TRC. Moreover, the present patient had a favorable prognosis given that she was disease free at her 113-month postoperative follow-up. Our case adds to the small body of literature on these exceptionally rare tumors and widens their clinicopathological spectrum.

Alveolar soft part sarcoma of uterine cervix in a postmenopausal woman: a case report and review of literature

We report a case of alveolar soft part sarcoma (ASPS) in a 68-year-old woman's uterine cervix. Macroscopic observation revealed an unencapsulated lesion confined to the cervical stroma, measuring 10 mm in diameter. Microscopic examination showed large, round or polygonal tumor cells, arranging in a well-defined nests pattern with scanty vascular stroma. Immunohistochemistry was performed. Tumor cells showed positivity for Ki-67 (2%), TFE-3, CD68, and myoD1 (cytoplasm) , while negative for HNF1β, CD10, RCC, PAX-8, CK7, CK18, CK8, CR, EMA, HMB-45, S-100, CgA, and Syn. Periodic acid-Schiff stain after diastase digestion (PAS-D) had revealed rod-like or rhomboid crystals of some cells. The diagnosis of ASPS was confirmed. ASPS was a rare soft tissue malignancy in female reproductive system. After a detailed study of the reported cases, we summarized some clinicopathological differences between cervical and soft tissue ASPS.

Melanotic MiT family translocation neoplasms: Expanding the clinical and molecular spectrum of this unique entity of tumors

MiT family translocation tumors are a group of neoplasms characterized by translocations involving MiT family transcription factors. The translocation renal cell carcinomas, TFE3 (Xp11.2) and TFEB (t6;11) are known members of this family. Melanotic Xp11 translocation renal cancer is a more recently described entity. To date only 14 cases have been described. It is characterized by a distinct set of features including a nested epithelioid morphology, melanin pigmentation, labeling for markers of melanocytic differentiation, lack of labeling for markers of renal tubular differentiation, predominance in a younger age population and association with aggressive clinical behavior. There are noted similarities between that entity and TFE3 associated PEComas. There are no cases reported of equivalent melanotic TFEB translocation renal cancer. We report 2 rare cases of melanotic translocation renal neoplasms. The first is a melanotic TFE3 translocation renal cancer with an indolent clinical course, occurring in a patient more than 3-decades older than the usual average age in which such tumors have been described. The other case is, to our knowledge, the first reported melanotic TFEB translocation cancer of the kidney. Both cases exhibit the same H&E morphology as previously reported in melanotic translocation renal cancers and label accordingly with HMB45 and Melan-A. While the TFE3 melanotic tumor lacked any evidence of renal tubular differentiation, the TFEB melanotic cancer exhibited some staining for renal tubular markers. Based on the unique features noted above, these two cases expand the clinical and molecular spectrum of the melanotic translocation renal cancers.

TFE3-Fusion Variant Analysis Defines Specific Clinicopathologic Associations Among Xp11 Translocation Cancers

Xp11 translocation cancers include Xp11 translocation renal cell carcinoma (RCC), Xp11 translocation perivascular epithelioid cell tumor (PEComa), and melanotic Xp11 translocation renal cancer. In Xp11 translocation cancers, oncogenic activation of TFE3 is driven by the fusion of TFE3 with a number of different gene partners; however, the impact of individual fusion variant on specific clinicopathologic features of Xp11 translocation cancers has not been well defined. In this study, we analyze 60 Xp11 translocation cancers by fluorescence in situ hybridization using custom bacterial artificial chromosome probes to establish their TFE3 fusion gene partner. In 5 cases RNA sequencing was also used to further characterize the fusion transcripts. The 60 Xp11 translocation cancers included 47 Xp11 translocation RCC, 8 Xp11 translocation PEComas, and 5 melanotic Xp11 translocation renal cancers. A fusion partner was identified in 53/60 (88%) cases, including 18 SFPQ (PSF), 16 PRCC, 12 ASPSCR1 (ASPL), 6 NONO, and 1 DVL2. We provide the first morphologic description of the NONO-TFE3 RCC, which frequently demonstrates subnuclear vacuoles leading to distinctive suprabasal nuclear palisading. Similar subnuclear vacuolization was also characteristic of SFPQ-TFE3 RCC, creating overlapping features with clear cell papillary RCC. We also describe the first RCC with a DVL2-TFE3 gene fusion, in addition to an extrarenal pigmented PEComa with a NONO-TFE3 gene fusion. Furthermore, among neoplasms with the SFPQ-TFE3, NONO-TFE3, DVL2-TFE3, and ASPL-TFE3 gene fusions, the RCCs are almost always PAX8 positive, cathepsin K negative by immunohistochemistry, whereas the mesenchymal counterparts (Xp11 translocation PEComas, melanotic Xp11 translocation renal cancers, and alveolar soft part sarcoma) are PAX8 negative, cathepsin K positive. These findings support the concept that despite an identical gene fusion, the RCCs are distinct from the corresponding mesenchymal neoplasms, perhaps due to the cellular context in which the translocation occurs. We corroborate prior data showing that the PRCC-TFE3 RCCs are the only known Xp11 translocation RCC molecular subtype that are consistently cathepsin K positive. In summary, our data expand further the clinicopathologic features of cancers with specific TFE3 gene fusions and should allow for more meaningful clinicopathologic associations to be drawn.

Melanotic Xp11 Translocation Renal Cancer Managed With Radical Nephrectomy and IVC Tumor Thrombectomy

Melanotic Xp11 translocation renal cancer is a rarely observed neoplasm primarily affecting adolescents and young adults. Given the paucity of data describing this malignancy, its natural history and subsequent long-term management are not well understood. We report a case of melanotic Xp11 translocation with tumor thrombus extension managed with radical nephrectomy and inferior vena cava (IVC) tumor thrombectomy. To our knowledge, this is the first case report to describe use of conventional tumor thrombectomy techniques in a patient with melanotic Xp11 translocation renal cancer.

Pigmented perivascular epithelioid cell tumor (PEComa) arising from kidney: A case report

INTRODUCTION

Perivascular epithelioid cell tumor (PEComa) is a mesenchymal neoplasm composed of perivascular epithelioid cells with clear to eosinophilic cytoplasm. Pigmented PEComa arising from kidney is extraordinarily rare and sometimes can exhibit aggressive biological behavior.

CASE REPORT

We present here a rare case of pigmented renal PEComa in a 46-year-old female. The patient had complained of lumbago complicated with nausea and vomiting for 2 weeks and therefore was referred to our department. An enhanced computed scan revealed a 4 × 3 × 3 cm round-like mass in the lower pole of right kidney with inhomogeneous enhancement. The tumor cells immunestained was positive for HMB-45, focally positive for c-Kit (CD117), and negative for vimentin, S-100, AE1/AE3, CK-7, CK-18, CD-10, RCC antigen, CgA, DOG-1, EMA, smooth muscle actin, and synaptophysin. We successfully performed 3-dimensional laparoscopic resection of the neoplasm, which was then diagnosed as pigmented PEComa by postoperative pathology. No further growing lesion or metastasis was observed during a 1-year follow-up.

CONCLUSION

This case report shows that pigmented renal PEComa is often presented as a renal mass with nonspecific symptoms and imaging features. The gold diagnosis of renal pigmented PEComa is mainly based on the combination of histopathology and immunohistochemistry. Complete resection by 3-dimensional laparoscopic nephron-sparing surgery can be an effective therapeutic management.

Xp11 neoplasm with melanocytic differentiation of the prostate harbouring the novel NONO-TFE3 gene fusion: report of a unique case expanding the gene fusion spectrum

Recently, an increasing number of TFE3 rearrangement-associated tumours have been reported, such as TFE3 rearrangement-associated perivascular epithelioid cell tumours (PEComas), melanotic Xp11 translocation renal cancers and melanotic Xp11 neoplasms. We have suggested that these tumours belong to a single clinicopathological spectrum. 'Xp11 neoplasm with melanocytic differentiation' or 'melanotic Xp11 neoplasm' have been proposed to designate this unique neoplasm. Herein, we describe the first case of an Xp11 neoplasm with melanocytic differentiation to be described in the prostate, bearing the novel NONO-TFE3 gene fusion. This study both adds to the spectrum regarding melanotic Xp11 neoplasms and expands its gene fusion spectrum. Moreover, we discuss the relationship of these rare tumours to neoplasms such as conventional PEComas, alveolar soft part sarcomas, malignant melanomas, clear cell sarcomas and Xp11 translocation renal cancers.

MiT Family Translocation-Associated Renal Cell Carcinoma: A Contemporary Update With Emphasis on Morphologic, Immunophenotypic, and Molecular Mimics

Translocation-associated renal cell carcinoma (t-RCC) is a relatively uncommon subtype of renal cell carcinoma characterized by recurrent gene rearrangements involving the TFE3 or TFEB loci. TFE3 and TFEB are members of the microphthalmia transcription factor (MiT) family, which regulates differentiation in melanocytes and osteoclasts, and MiT family gene fusions activate unique molecular programs that can be detected immunohistochemically. Although the overall clinical behavior of t-RCC is variable, emerging molecular data suggest the possibility of targeted approaches to advanced disease. Thus, distinguishing t-RCC from its morphologic, immunophenotypic, and molecular mimics may have important clinical implications. The differential diagnosis for t-RCC includes a variety of common renal neoplasms, particularly those demonstrating clear cell and papillary features; in addition, because of immunophenotypic overlap and/or shared molecular abnormalities (ie, TFE3 gene rearrangement), a distinctive set of nonepithelial renal tumors may also warrant consideration. Directed ancillary testing is an essential aspect to the workup of t-RCC cases and may include a panel of immunohistochemical stains, such as PAX8, pancytokeratins, epithelial membrane antigen, carbonic anhydrase IX, HMB-45, and Melan-A. Dual-color, break-apart fluorescent in situ hybridization for TFE3 or TFEB gene rearrangement may be helpful in diagnostically challenging cases or when molecular confirmation is needed.

PSF/SFPQ is a very common gene fusion partner in TFE3 rearrangement-associated perivascular epithelioid cell tumors (PEComas) and melanotic Xp11 translocation renal cancers: clinicopathologic, immunohistochemical, and molecular characteristics suggesting classification as a distinct entity

An increasing number of TFE3 rearrangement-associated tumors, such as TFE3 rearrangement-associated perivascular epithelioid cell tumors (PEComas), melanotic Xp11 translocation renal cancers, and melanotic Xp11 neoplasms, have recently been reported. We examined 12 such cases, including 5 TFE3 rearrangement-associated PEComas located in the pancreas, cervix, or pelvis and 7 melanotic Xp11 translocation renal cancers, using clinicopathologic, immunohistochemical, and molecular analyses. All the tumors shared a similar morphology, including a purely nested or sheet-like architecture separated by a delicate vascular network, purely epithelioid cells displaying a clear or granular eosinophilic cytoplasm, a lack of papillary structures and spindle cell or fat components, uniform round or oval nuclei containing small visible nucleoli, and, in most cases (11/12), melanin pigmentation. The levels of mitotic activity and necrosis varied. All 12 cases displayed moderately (2+) or strongly (3+) positive immunoreactivity for TFE3 and cathepsin K. One case labeled focally for HMB45 and Melan-A, whereas the others typically labeled moderately (2+) or strongly (3+) for 1 of these markers. None of the cases were immunoreactive for smooth muscle actin, desmin, CKpan, S100, or PAX8. PSF-TFE3 fusion genes were confirmed by reverse transcription polymerase chain reaction in cases (7/7) in which a novel PSF-TFE3 fusion point was identified. All of the cases displayed TFE3 rearrangement associated with Xp11 translocation. Furthermore, we developed a PSF-TFE3 fusion fluorescence in situ hybridization assay for the detection of the PSF-TFE3 fusion gene and detected it in all 12 cases. Clinical follow-up data were available for 7 patients. Three patients died, and 2 patients (cases 1 and 3) remained alive with no evidence of disease after initial resection. Case 2 experienced recurrence and remained alive with disease. Case 5, a recent case, remained alive with extensive abdominal cavity metastases. Our data suggest that these tumors belong to a single clinicopathologic spectrum and expand the known characteristics of TFE3 rearrangement-associated tumors.

PEComa: morphology and genetics of a complex tumor family

Perivascular epithelioid cell tumors, or PEComas, are mesenchymal neoplasms composed of histologically and immunohistochemically distinctive epithelioid or spindle cells, which are immunoreactive for both smooth muscle and melanocytic markers. The cells in PEComas are typically arranged around blood vessels and appear to form the vessel wall, often infiltrating the smooth muscle of small- to medium-sized vessels. Periluminal cells are usually epithelioid and the more peripheral cells are spindle shaped. The cells have small, round to oval nuclei, sometimes with focal nuclear atypia, and clear to eosinophilic cytoplasm, and no counterpart normal cell has been identified. The PEComa "family" now includes angiomyolipoma, pulmonary clear cell "sugar" tumor and lymphangioleiomyomatosis, primary extrapulmonary sugar tumor, clear cell myomelanocytic tumor of the falciform ligament/ligamentum teres, abdominopelvic sarcoma of perivascular epithelioid cells, and other tumors with similar features at various sites that are simply termed PEComa. Some PEComas occur in patients with tuberous sclerosis complex and share the genetic abnormalities. There is a behavioral spectrum from benign to frankly malignant, and histologic criteria have been proposed for assessing malignant potential. The differential diagnosis can include carcinomas, smooth muscle tumors, other clear cell neoplasms, and adipocytic tumors. PEComas constitute a genetically diverse group that includes neoplasms harboring TFE3 gene rearrangements and those with TSC2 mutations, indicating alternative tumorigenic pathways. Recent advances in therapy of malignant PEComas relate to increased knowledge of specific genetic changes and their effects on metabolic pathways that are susceptible to specific interventions. We review PEComas, emphasizing the diagnostic spectrum and recent immunohistochemical and genetic findings.